Bearing with oil film thickness measuring device

A bearing with an oil film thickness measuring device in which sensor portions at distal ends of four common optical fibers are connected to sensor mounting portions formed at four positions in an axial direction of a bearing body. A lubricating oil containing a fluorescent agent is supplied to a sliding surface of the bearing body. A laser beam generated from a laser beam generator is branched into four beams, which are applied to an oil film on a sliding surface through each of sensor portions. Fluorescence generated by the fluorescent agent in the oil film, passing through a return-route optical fiber, is introduced into a photomultiplier tube, and is detected. Since the fluorescence intensity detected by the photomultiplier tube is proportional to the thickness of oil film, the absolute value of oil film thickness can be measured. In this case, the oil film thickness can be measured at four positions.